Gas prices in the U.S. have fallen below $4 per gallon for the first time since mid-April, driven by a diplomatic breakthrough between the U.S. and Iran. The deal, announced by President Donald Trump, aims to reopen the Strait of Hormuz, a critical chokepoint through which about 20% of the world’s oil flows. Oil prices responded quickly, with Brent crude dropping to around $83 per barrel—a nearly 12% decline over the week.

The conflict began on February 28 when the U.S. and Israel launched attacks on Iran, prompting Iran to block the strait and triggering a global energy crisis. Since then, oil prices have remained elevated, and gas prices followed. The current national average for regular gasoline is $3.99, down 52.4 cents from a month ago, according to GasBuddy.

While the framework of the deal has been agreed upon, full implementation will take time. Mines in the waterway and varying risk tolerances among shipping crews mean that traffic through the strait will ramp up slowly. A senior U.S. official estimates it could take about two weeks to return to normal levels. Even then, analysts caution that the market remains fragile and the durability of this relief depends on sustained diplomatic progress.